Traditionally, pasta filata cheese is manufactured by a laborious process of hand working, including, using a culture to make cheese curd, kneading the curd in extremely hot water, being careful not to overknead, thus resulting in less loss of fat from the cheese, molding the cheese and cooling and brining of the hand made cheese. Naturally enough, this process is extremely time consuming and, from a practical standpoint, is not easily applicable to the manufacture of cheese in large commercial quantities.
Nevertheless, this process of manufacturing remained relatively unchanged until very recently. One major step in the development of processes for the commercial manufacture of pasta filata or mozzarella cheese was introduced by me in the 1970's and is described in my U.S. Pat. No. 4,112,835 directed to a cheese processing system. In this patent I describe, among other things, a machine for molding and cooling the cooked and kneaded cheese curd. In accordance with this process, a plurality of molds are disposed on a rotating table which also supports a cooling tank within which the cheese molds are contained. In this machine, which is, today, substantially the only practical and widely employed mozzarella molding machine available on the market, as the table is rotated, cheese is fed from the under side of the table into the molds. At the same time, the molds are subjected to a bath of circulating coolant, such as glycol brine or chilled water. As the table rotates different molds are filled with cheese and after completing the rotary cycle, the contents of the mold are ejected and sent down the manufacturing line to a downstream manufacturing process steps. Such downstream processing steps include salting in brine for a period of time packing and curing the completed packed cheese during which time the salt in the rind, formed during the salting process, salt migrates toward the center of the cheese to give it the desired consistency, meltability and flavor.
In order to more fully understand the subject matter of the invention, it is valuable to note that the manufacture of mozzarella cheese falls, generally, into two catagories. The first catagory is the manufacture of large (greater than two kilogram cheeses). In accordance with the presently employed commercial methods for the manufacture of such big cheeses, the cooked and kneaded cheese curd is fed into the metal molds in an apparatus such as that illustrated in FIG. 2 in my earlier patent. After being fed into the mold, the molded cheese rotates on the table in the cooling bath until it is ejected from the machine. Because the cheese is large, cooling is relatively ineffective and it is necessary to put the ejected cheese, which has been metered accurately in terms of weight, into a forming tray made of plastic or stainless steel. Once the forming tray has been filled with a single cheese, the forming tray is then put in a bath of cold water for about one half to one and one half hours to cool it from its very high core temperature. After an hour or so, the core of the cheese has had its temperature lowered from 55.degree. C. to the range of 5.degree.-35.degree. C. At this point, the cheese is sufficiently cooled that it will maintain its shape and may be then placed in a brine tank for further cooling and salting. The cheese is kept in the brine tank for approximately twenty-four hours, during which time it develops a salty rind. The cheese is then removed from the brine and packaged. However, the cheese is not suitable for use at this time because the salt is concentrated in the outer layers of the cheese. There is thus substantially no salt at the core of the cheese. It is necessary for reasons of meltability, flavor, avoidance of burning and preservation that the salt permeate through to the core of the cheese. Accordingly, it is necessary to cure the packaged big cheese in a refrigerated warehouse or box for about 1,000 hours, during which time the salt in the rind permeates through to the center of the cheese. After the 1,000 hour curing process, the cheese may then be used with best results.
In the case of the smaller cheeses, such as those having a weight on the order of 0.25 to 0.5 kilograms, a similar process is employed, but, because the smaller size of the cheese and the consequent ability to be cooled more quickly and thus hold its shape, slightly different steps are used. In particular, such small cheeses are molded in a machine such as that illustrated in FIG. 2 of my earlier patent. However the machine is modified to the extent that a sizing sleeve is added to the mold's plunger as illustrated in FIG. 4 of my patent. After molding, the cheese in the molds is rotated on the table all the time being cooled by the bath surrounding the molds. After completing the rotating cooling cycle in the machine, the cheese is then ejected from the machine and is further cooled and salted in brine for about 1-2 hours. Because the cheese is smaller, the cheese cools to a much greater extent in the molding machine and, accordingly, holds its shape upon ejection from the machine into the brine and thus need not be put into a forming tray. After being salted in the brine for 1-2 hours, the small cheese is packed and is allowed to cure overnight, allowing salt to penetrate to the center of the cheese before use by the consumer.
While the machinery which I described in my earlier patent is a great advance over the methods previously employed in the art, there still are, and the industry has for many years now, tolerated a number of significant problems, including, in the case of big cheeses the necessity for molding trays, long salting times and long curing times. It is obvious that the use of trays for molding the cheese shape is a manual operation involving the loading, handling and cleaning of trays and the moving of the cheese manually from one step to another. The salting of cheese for a period of twenty-four hours is another time consuming step which reduces the number of pounds of cheese per hour that can be manufactured as well as resulting in a great number of trays being needed. Likewise, curing the cheese for a period of twelve to fourteen days, as is commonly done in the industry today, involves a phenomenal expense in view of the fact that the cheese being cured must be refrigerated and takes up a great deal of expensive floor plant space. In the case of the small cheese, all the problems described above exist, but to a lesser degree owing to the smaller size of the cheese. Nonethelss, there are significant limitations on the production rate at which cheese may be manufactured.
In an attempt to overcome the problems involved in prior art cheese making methods and to increase the yield in kilograms per hour of cheese, various techniques have been attempted. One commonly employed expedient is the cooking of the curd and the kneading of the curd in a hot bath to which salt has been added. However, this technique, while it does introduce a few tenths percent of salt into the cheese is not sufficient to obtain the desired two percent concentration of salt needed regardless of size. In addition, this process appears to lessen the quality of the cheese. Even more important, the whey cream, which is a by-product of the separated cooking water in the manufacture of pasta filata must, of necessity, includes a great deal of salt under this alternative process and, accordingly, is not as desirable on the commercial market. Finally, this alternative process does nothing to solve the problem of the handling of trays and the multiplicity of baths in the case of big cheeses. Still other problems attend present day manufacturing techniques.
The slow cooling of the cheese in the machine results in the ejection of cheese with a core center that is relatively hot and, accordingly, warms up the first brine bath. It is thus necessary to maintain the brine baths at a desirably low temperature at great cost. Due to the fact that cooling takes a relatively long amount of time, the cheese thus manufactured tends to have a shorter shelf life due to bacterial activity. These disadvantages as well as the other disadvantages described above with respect to present day manufacturing techniques are in accordance with the present invention substantially alleviated.